It has been proposed previously to provide an air-bag in the form of an inflatable curtain, the air-bag being configured to be mounted in a motor vehicle along the roof line of the vehicle above the doors. The air-bag is associated with a gas generator to inflate the air-bag in the event that an accident should occur. The inflated air-bag is intended to extend between an occupant of the vehicle and the adjacent doors.
Many designs of inflatable curtain have been proposed previously but reference is made to FIG. 1 of the accompanying drawings which illustrates a typical design.
Referring initially to FIG. 1, an air-bag 1 in the form of an inflatable curtain in accordance with the prior art has a main region 2 of generally rectangular form, the main region incorporating a first inflatable zone 3 divided into a plurality of cells 4 by seams 5, and a second inflatable zone 6 divided into cells 7 by means of seams 8. The two inflatable zones 3 and 6 are separated by a substantially uninflatable zone 9.
A first projection 10 is provided at one end of the lower edge of the inflatable curtain, to be connected to a strap, and a further projection 11 is provided at the other end of the lower edge to be connected to a further strap.
Along the upper edge of the air-bag, a gas flow duct 12 is provided which communicates with the inflatable cells of the first zone 3 and the inflatable cells of the second zone 6. The gas duct 12 is provided with an end portion 13 configured to be connected to a gas generator. The uppermost edge 14 of the air-bag is provided with a plurality of evenly spaced mounting tabs 15 each being provided with an aperture 16.
The air-bag as described is one example of many different designs of air-bag of the inflatable-curtain type that are in use.
In the described arrangement, the mounting tabs 15 are formed of a single layer of fabric. However, it has been found that the mounting tabs 15 may not be sufficiently strong to withstand the forces applied to the mounting tabs during deployment of the air-bag. Here it is to be understood that the air-bag is deployed within a very brief period of time in response to a signal from a sensor responsive to a side impact or rollover situation. The gas that inflates the air-bag is injected into the gas flow duct 12 in a very aggressive manner, and it is not unknown for the mounting tabs 15 to become damaged as a result.
It has been proposed to modify the mounting tabs either by providing a stitched re-enforcement or, alternatively, by forming the tabs by initially providing an over-sized piece of fabric at the position where each tab is to be, and then folding the fabric over and effecting a stitching operation to provide a mounting tab of enhanced strength. Such techniques are, however, undesirable as they are labour intensive and therefore costly.